People with Autism Have Lower Levels of a Key Endocannabinoid

Blood anandamide (AEA) levels were significantly lower in individuals with ASD (SMD=-0.79, p=0.002) compared to controls. In animal models, hippocampal AEA was also significantly decreased (SMD=-1.06, p<0.01), and prefrontal cortex 2-AG was reduced (SMD=-1.00, p=0.04). Narrative synthesis found that elevating AEA and 2-AG levels improved core autistic-like symptoms in animal models, with region- and sex-dependent variations.

Systematic review and meta-analysis of 16 animal studies and 5 human studies on endocannabinoid system alterations in ASD. Random-effects meta-analysis for quantitative synthesis.

If endocannabinoid deficiency contributes to autism symptoms, targeted therapies that raise endocannabinoid levels (such as FAAH inhibitors or potentially CBD) could represent a novel treatment approach.

The endocannabinoid system regulates social behavior, emotional processing, and sensory integration, all of which are affected in autism. These findings provide biological plausibility for the growing interest in cannabinoid-based interventions for ASD.

Only 5 human studies available. High heterogeneity in some analyses. Animal models of autism may not fully reflect human ASD. Blood endocannabinoid levels may not reflect brain levels. Various ASD models and species used across studies.